Technical Status and Development Trends of Difficult Throttles Treatment Technology in Gas Wells

Abstract In order to promote the development of treatment technology for difficult throttles in gas wells and assist in solving the problem of gas well shutdown caused by the failure of difficult throttle treatment, this paper delves into the structural principles of preset throttles and slip-type throttles, introducing various types such as preset wire deployment and fishable throttles, preset non-wire deployment and fishable throttles, mechanical slip-type throttles, and electric throttles. It systematically analyzes the difficulties in retrieving difficult throttles, including wire breakage, fishing head breakage, deformation and breakage of slips, eccentric fishing head, non-release of inflated rubber cylinder, jamming, sand burial, scaling, fluid accumulation, falling objects underground, tubing deformation, and complex production tubing strings. Furthermore, it sequentially introduces weighted steel wire fishing treatment, coiled tubing fishing treatment technology, milling and fishing stuck throttles treatment, snubbing operation treatment technology, and well killing and workover treatment technology, which encompass punching holes in the tubing treatment technology, tubing cutting technology under pressure and sand flushing technology. The shortcomings of each treatment technique are also highlighted. Taking into account the current challenges faced in the treatment of difficult throttles, such as high cost and low efficiency in low-pressure gas wells, poor technical adaptability, and high risk of operational failure, it is pointed out that future difficult throttle processing technology should focus on two key directions. Firstly, it should aim for non-well-killing and low-cost development. Secondly, it should strive to reduce the occurrence and treatment difficulty of difficult throttles from the source design. And it provides technical references and ideas for the design of the next generation throttles.